半刚性连接高层钢框架P-△效应分析的简化方法

A SIMPLIFIED P-△ EFFECTS ANALYSIS APPROACH FOR TALL BUILDING STEEL FRAMES WITH SEMI-RIGID CONNECTIONS

介绍一个半刚性连接高层钢框架P-△效应分析的实用简化方法。以部分框架为分析子单元,用变刚度的转动弹簧模拟梁柱节点连接的半刚性,建立了考虑P-△效应的半刚性连接高层钢框架内力和位移计算的无迭代简化公式。算例表明,梁柱连接的半刚性确实降低了钢框架的抗剪刚度,明显增加了结构的水平位移和P-△效应,应当在高层钢框架的P-△效应分析中考虑半刚性连接的影响。该方法不仅简单实用,便于手算,而且精度较高,可供工程设计人员在半刚性连接高层钢框架设计时使用。影响半刚性连接高层钢框架P-△效应的主要因素是柱的抗剪刚度、梁与柱的线刚度之比、半刚性连接的类型和相应的连接刚度系数α值。

A practical yet simplified method for P-△ effects analysis of tall building steel frames with semi-rigid connections is presented. By taking partial frame as an analytical subassembly element and using a rotation spring which has variable bending stiffness to model semi-rigid of beam-column connection, this paper derives a simplified non-iterative inner force and lateral deflection computation formula taking into account P-△ effects for tall building steel frames with semi-rigid connections. The numerical examples show that semi-rigid of beam-column connections indeed decreases the lateral shear stiffness of steel frames and obviously increases the horizontal displacement and P-△ effect on the steel frame. Therefore, the influences of semi-rigid connection should been considered in P-△ effects analysis of tall building steel frames. The presented method is not only relatively simple, practical and easily applicable to manual computation but also has a rather high accuracy, and can be used by the engineers in preliminary design for tall building steel frames with semi-rigid connections. The main effect factors of P-△ effects in a tall building steel frame with semi-rigid connections are the column shear stiffness, the proportion of the beam liner stiffness to column liner stiffness as well as the different form of semi-rigid connections and connection rigid coefficient a.